Custom item crafting

I'm newbie in the plugin programming, so I would like to hear some solution to my problem.
Problem:
On the server there is a custom craft of the so-called "Reinforced iron". Craft consists of 4 pieces of ordinary iron. The screenshot below.

Code:

Code:

ItemStack c_iron = new ItemStack(Material.IRON_INGOT);
        ItemMeta c_iron_meta = c_iron.getItemMeta();
     
        List<String> lore = new ArrayList<String>();
        c_iron_meta.setDisplayName("§fReinforced iron");
        c_iron_meta.addEnchant(Enchantment.ARROW_INFINITE, 10, true);
        lore.add("§7Used to make chain mail.");
        c_iron_meta.setLore(lore);
        c_iron.setItemMeta(c_iron_meta);
     
        ShapedRecipe ciron1 = new ShapedRecipe(c_iron);
        ciron1.shape("** ","** ","   ");
        getServer().addRecipe(ciron1);
     
        ItemStack c_helmet = new ItemStack(Material.CHAINMAIL_HELMET);
        ShapedRecipe chelmet1 = new ShapedRecipe(c_helmet);
        chelmet1.shape("***","* *","   ");
        chelmet1.setIngredient('*', /*my custom material here*/);

And I would like that this iron was used for crafting chain mail armor

 

What exactly is your problem? Everything seems to work fine.

 

@EdwardHyde
Last time I checked it was not possible to do this. You have to check for PrepareItemCraftEvent.